Abstract

The DFT-PW91 slab model approach is employed to investigate the influence of aggregation, surface defects, and contaminant oxygen on waterdissociation on Cu(110) at low temperatures. The dissociation barriers of water in various aggregate states are calculated in the range of on the clean surfaces, in nice agreement with the experimentally determined values. It is revealed that the aggregation of water shows no propensity to reduce the activation barrier for the O–H bond breaking on Cu(110), at variance with the water chemistry on Ru(0001). The calculated activation energy on Cu(211) which is the most active stepped surface investigated is equal to the value on the (110) surface, indicating that the hydroxyl groups observed on Cu(110) at low temperatures may not stem from surface defects. The coadsorbed oxygen, whether as a “spectator” or a “participant,” facilitates the waterdissociation both kinetically and thermodynamically.

Received 04 January 2007Accepted 28 May 2007Published online 12 September 2007

Acknowledgments:

This work was supported by a Foundation for the Author of National Excellent Doctoral Dissertation of P.R. China (No. 200123) and the Natural Science Foundation of China (NSFC2003CB615804). The authors gratefully acknowledge the Computing Center of Nanjing University for the computer time. One of the authors (Q.-L.T.) is indebted to Dr. X. He for the valuable discussions.

Article outline:I. INTRODUCTIONII. MODELS AND COMPUTATIONAL DETAILSIII. RESULTS AND DISCUSSIONA. Adsorption complexes on Cu(110), Cu(211), and 1. Atomic hydrogen2. Hydroxyl group3. Water dimers on Cu(110) and Cu(211)4. Watermonomers on B. Waterdissociation on various surfaces1. on Cu(110)2. on Cu(211)3. Waterdissociation on C. Comparison of various pathways of water decompositionIV. CONCLUSIONS